Employing Non-Hermitian matrices in understanding open quantum systems

Various quantum systems can be viewed as open quantum systems due to the presence of noise, dissipations and other sources of decoherence in experimental setups. Theoretically, these systems are studied by either solving the full master equation or using effective formulations based on non-Hermitian physics. While the former approach is widely known, it is challenging in obtaining analytical and numerical solutions and connecting their outcome with experimental measurements. The latter approach evaluates effective descriptions employing non-Hermitian physics, which has been the focus of numerous studies in recent years. Interestingly, for a given open quantum system multiple non-Hermitian matrices can be determined. In this talk, I will present similarities and distinctions between various non-Hermitian treatments and focus on several experimentally feasible examples. I will show how unique features of non-Hermitian systems, namely exceptional points, emerge in these systems.